The laying of tiles and coverings composed of tiles, floor tiles or slabs of medium or large size with reduced or lowered thickness typically is more difficult during the steps for leveling the laying and for equally spacing the tiles in order to provide the gaps.
Leveling spacers are currently known for laying tiles, floor tiles and the like which are constituted by a base, to be arranged below two laterally adjacent tiles; spacing protrusions, shaped substantially like a parallelepiped, extend from such base in order to define the width of the gaps and in fact define the abutments for the edges of the tiles.
By arranging for example two leveling spacers at each side of a tile, preferably proximate to each corner, one obtains for such tile the desired planarity, and at the same time correct placement is sought with respect to the tiles that surround it and also are laid with other identical leveling spacers.
A flat tab protrudes from the base of the leveling spacer, is extended so as to exit from the channel defined between the tiles in order to provide the gap, and is provided with an opening for insertion of a tile locking wedge between the surface of the tile and the upper edge of the opening.
Such wedge-type locking system has two functions: locking the edges of the laterally adjacent tiles between such wedge and the base of the leveling spacer, ensuring co-planner arrangement during the laying of the tiles, removing the tabs of the respective bases for the provision of the gaps by striking the wedge in the direction of insertion in the window of such tab.
Another similar leveling spacer has a toothed strap-like tab that extends from the base with spacers and is preset to be inserted in a locking body, which in turn is adapted to be pressed so as to straddle the two laterally adjacent edges of the nearby tiles.
Such leveling spacers, while being widespread and appreciated, suffer drawbacks, such as actual difficulty in removing the tab by striking the wedge, and the use of an adapted tool to perform the correct and useful coupling between the strap and the locking body in order to lock the tiles between the locking body and the base of the spacer, said use in fact requiring the availability of said tool and a certain time both for placement and for removal.
In order to obviate these drawbacks, a leveling spacer for laying tiles, floor tiles and the like with the interposition of gaps has been devised which is the subject of Italian patent application PD 2011 A 295 by Progress Profiles S.p.A. filed on Sep. 20, 2011.
Such leveling spacer is characterized in that it comprises                a base with abutment spacing protrusions for the edges of corresponding tiles, in order to define the width of the gaps,        a threaded stem, which is fixed at right angles to the base in at least one preweakened point,        a knob for gripping and removing the threaded stem, which comprises a female thread portion that is adapted to be screwed to said threaded stem.        
The possibility to screw the knob on the threaded stem allows to adapt the leveling spacer according to the disclosure to tiles, floor tiles and slabs having thicknesses from 3 millimeters up to 30 millimeters, and optionally more, providing an adapted longer stem.
The knob can of course be reused.
The disclosure provides a leveling spacer that is easy and intuitive to use both during assembly for locking the tiles and during removal for the subsequent provision of the gaps, a screwing operation being required and sufficient for both steps.
Such leveling spacer, while being appreciated and advantageous for the reasons described above, has an aspect that can be improved, which is linked to the fact the operation for screwing the knob to the threaded stem entails that the last turns are imparted to the knob when it is in contact with the tiles, for better grip of the spacer to the tiles, with consequent assurance of the planarity among laterally adjacent tiles.
Such rotation of the knob in contact with the tiles can cause a highly unwanted slippage of said tiles, caused by the knob alone or, worse still, if typical building yard debris, such as grains of building material and the like, become interposed between the tile and the knob.
Such phenomenon of tile slippage is even more conspicuous if the knob is screwed on to separate the threaded stem, inevitably entailing an increase in the pressure of said knob on the tiles.